Plasmonics for THz frequency applications

In this contribution we concentrate on two aspects of THz science related to surface and particle plasmons. Firstly, we report on the generation of THz pulses via irradiation of arrays of silver nanoparticles by femtosecond laser pulses. We propose that this effect arises from the emission of photoelectrons by multi-photon excitation and subsequent acceleration of these emitted electrons by ponderomotive forces associated with the optical fields of the plasmons in the metallic nanostructures. Secondly, we demonstrate that semiconductors supports strongly confined surface plasmons in the THz frequency range. We show that these SPs can be utilized to enhance the light-matter interaction with dielectric layers above the semiconductor surface, thereby allowing us to detect the presence of layers around one thousand times thinner than the free space wavelength of the THz light. We discuss the viability of using semiconductor SPs for the purposes of THz sensing and spectroscopy.